Whole Blood Interferon-gamma Release Assay Is Insufficient for the Diagnosis of Sputum Smear Negative Pulmonary Tuberculosis.
10.3349/ymj.2014.55.3.725
- Author:
Heejin PARK
1
;
Jung Ar SHIN
;
Hyung Jung KIM
;
Chul Min AHN
;
Yoon Soo CHANG
Author Information
1. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea. yschang@yuhs.ac
- Publication Type:Original Article ; Research Support, Non-U.S. Gov't
- Keywords:
Sputum smear negative pulmonary tuberculosis;
interferon-gamma release assay;
active pulmonary tuberculosis
- MeSH:
Adult;
Aged;
Female;
Humans;
Interferon-gamma Release Tests/*methods;
Male;
Middle Aged;
Retrospective Studies;
Sputum/*microbiology;
Tuberculosis, Pulmonary/blood/*diagnosis/metabolism
- From:Yonsei Medical Journal
2014;55(3):725-731
- CountryRepublic of Korea
- Language:English
-
Abstract:
PURPOSE: We investigated the value of an interferon-gamma release assay (IGRA) for the diagnosis of active pulmonary tuberculosis (PTB) among sputum smear negative PTB suspects in an environment with intermediate burden of PTB and high Bacillus Calmette-Guerin (BCG) vaccination rate. MATERIALS AND METHODS: We retrospectively reviewed IGRA, medical records, chest PA and CT scan of PTB suspects seen at Gangnam Severance Hospital, Seoul, Korea from Oct. 2007 to Apr. 2013. "Active PTB" was diagnosed when 1) M. tuberculosis culture positive, 2) confirmation by pathologic examination; or 3) clinical findings compatible with TB. RESULTS: Of 224 sputum smear negative PTB suspects, 94 were confirmed as having active PTB. There were no statistically significant differences in the diagnostic yield of IGRA between immunocompromised and immunocompetent sputum smear negative PTB suspects. IGRA did show superior sensitivity [81.9%, 95% confidence interval (CI); 74.13-89.70%] in the diagnosis of sputum smear negative PTB when compared with chest high-resolution computed tomography (HRCT), tuberculin skin test (TST), and chest X-ray (p<0.001). Also, IGRA showed highest negative predictive value (82.7%, 95% CI; 75.16-90.15%) when compared with HRCT, TST and chest X-ray (p=0.023). However, combining the results of IGRA with those of HRCT, TST, or both did not increase any diagnostic parameters. CONCLUSION: Failure to increase diagnostic yields by combination with other diagnostic modalities suggests that additional enforcement with IGRA may be insufficient to exclude other diagnoses in sputum smear negative PTB suspects and to screen active PTB in an environment with intermediate TB prevalence and a high BCG vaccination rate.
